In bolting in narrow drifts in mines, there is often a conflict between the desired advance per round for the blast hole drilling and the feeding length in bolt drilling. If the required length for the blasting was to be drilled, the feeder would be so long that it would not be possible for it to be arranged transversely in the drift. One way of solving this problem is to use a feeder with displaceable drilling supports or to use a telescopic feeder. A telescopic feeder has a lower beam and an upper beam which is slidably arranged on the lower beam. The length of the telescopic feeder may be changed so that it may be extended to the desired length in a drilling condition and retracted which results in that it may be accommodated transversely in the drift when needed. One problem with telescopic feeders is that they are heavy and ungainly.
An example of a telescopic feeder is disclosed in WO9518912. This telescopic feeder comprises a lower beam and an upper beam slidably mounted on the lower beam. The slide rail, intended for the sliding arrangement between the upper beam and the lower beam, is placed solely on the lower portion of the upper beam which makes the lower beam low. This results in a reduced height of the telescopic feeder. The disadvantage of this design is that the upper beam becomes heavy and ungainly. This is in particular a problem when the feeder is used in a position where it has been rotated somewhat around its axis. The leverage with a heavier upper beam and lighter lower beam will then result in impaired friction between the beams.